(a) Field of the Invention
The present invention relates to a suspension system for vehicles. More particularly, the present invention relates to a suspension system for vehicles that can be mounted utilizing a minimal amount of space and in which irregularities in the road surface are not directly transmitted to a frame of the vehicle.
(b) Description of the Related Art
The suspension system in vehicles improves ride comfort by absorbing shocks received through the wheels when the same encounter surface irregularities in the road. In addition to this main capability, suspension systems must also be designed to provide directional control, ease of handling, safety and stability.
Suspension systems comprise one or more control arms connecting the frame to the wheels, and springs and shock absorbers to absorb shocks transmitted from the road surface in the vertical direction. Accordingly movement of the wheels in relation to the frame is fully supported such that shocks and vibrations resulting from surface irregularities of the road are absorbed, and stability is provided when steering the vehicle.
The suspension system must satisfy three basic criteria: (1) ability to absorb shocks caused by road surface irregularities to provide ride comfort to the driver and passengers; (2) ability to prevent swaying of the vehicle during cornering, acceleration and braking; and (3) ability to maintain an appropriate level of vertical load on a surface of the wheel contacting the road such that vehicle stability is provided while turning, braking and accelerating, even when surface irregularities in the road are encountered.
To improve the above capabilities, those in the industry have put forth much effort into overall improvement and refinement of the suspension system, and in the development of improved springs and damping mechanisms.
The single control arm suspension system, also called the McPherson strut suspension system, is one example of a conventional suspension system. As shown in FIG. 11, the conventional strut-type suspension system comprises a strut assembly 212 consisting of a shock absorber 204 and a coil spring 202, the coil spring 202 surrounding the shock absorber 204; an insulator 206 interposed between a vehicle body 208 and an upper end of the strut assembly 212; a wheel carrier 210 fixed to a lower end of the shock absorber 204 and to which a wheel is rotatably mounted; and a lower control arm 216 which connects a lower portion of the wheel carrier 210 to a sub-frame 214.
With this structure, upward movement of the wheel and wheel carrier 210 caused by surface irregularities in the road is absorbed by the strut assembly 212. Accordingly, only a minimal amount of shock is transmitted to the vehicle body 208 and the frame 214.
However, problems result from such mounting of the strut assembly 212 in a vertical or slightly slanted state. That is, because of this vertical or near-vertical mounting of the strut assembly 212, a substantial amount of space is used by the suspension system. As a result, the vehicle body 208 must be large to provide sufficient clearance for the suspension system to operate. This acts to reduce the size of the engine and passenger compartments and limits the free layout design of the suspension system.
Further, as a substantial load is concentrated on the area of the vehicle body 208 to which the upper end of the strut assembly 212 is mounted, this area can weaken and eventually become damaged from the stress received. This results in the generation of vibrations such that handling and ride comfort are negatively affected, and noise is generated.
To remedy the above problem, some conventional configurations reinforce this area of the wheel carrier 208 to which the strut assembly 212 is mounted. However, such an addition increases overall manufacturing costs and the weight of the vehicle.
In the above, although the strut-type suspension system was given by way of example, the same drawbacks apply to all vertically-mounted suspension systems including the double wishbone suspension system and the multi-link type suspension system.